Flat-type image display apparatus with insulating positioning members

Abstract

In a flat-type image display apparatus, thermal distortion caused by the exposure to high temperature is absorbed, thus obtaining assembly precision and maintaining it during operation. The apparatus comprises a flat type screen and a back electrode opposing the flat type screen. In the space between the flat type screen and the back electrode, linear cathodes and an electrode unit including an electron beam extracting electrode are arranged. Positioning members formed of heat-resistant insulators having guide portions for supporting the linear electrodes are attached to the electrode unit. The linear cathodes are positioned by the guide portions to keep a predetermined positional relationship with electron-beam extracting holes formed in the electron beam extracting electrode.

What is claimed is:  
     
       1. A flat-type image display apparatus comprising: 
       a cavity formed by a front case and a rear case connected to each other, the cavity being kept under vacuum;  
       a flat type screen formed on the front case;  
       a back electrode opposing the flat type screen;  
       an electrode unit including an electron beam extracting electrode with electron-beam extracting holes, a signal electrode, a focusing electrode, a horizontal deflection electrode, and a vertical deflection electrode, which are arranged in the space between the flat type screen and the back electrode;  
       linear cathodes extending in a predetermined positional relation with the electron beam extracting electrode; and  
       positioning members being disposed at both ends of the linear cathodes and attached to the electrode unit, which are formed of heat-resistant insulators and have guide portions for being contact with the linear electrodes, the  
       wherein, through the contact with the guide portions, the linear cathodes are positioned both in the horizontal direction within the plane of the flat type screen and in the vertical direction perpendicular to the plane, so that the linear electrodes keep the predetermined positional relationship horizontally with the electron-beam extracting holes and vertically with the electron beam extracting electrode.  
     
     
       2. A flat-type image display apparatus according to claim  1 , wherein the positioning members comprise: 
       horizontal positioning members incorporated into the electrode unit and having a horizontal guide portion for supporting a linear cathode horizontally that projects from the electron beam extracting electrode toward the back electrode; and  
       a pair of vertical positioning member attached to the electron beam extracting electrode and positioning the linear cathodes vertically with a vertical guide portion.  
     
     
       3. A flat-type image display apparatus according to claim  1 , wherein each of the positioning members comprises a horizontal guide portion for supporting the linear cathode horizontally and a vertical guide portion for supporting the linear cathodes vertically, the positioning member being provided for each linear cathode respectively. 
     
     
       4. A flat-type image display apparatus according to claim  3 , wherein the electron beam extracting electrode has attachment holes provided for each row of the electron-beam extracting holes for attachment of the positioning members, the attachment holes comprising an insertion portion, a supporting reference portion, and a pawl for preventing the positioning members from slipping off; and 
       the positioning members are inserted into and set in the attachment holes.